Dysregulated NUB1 and neddylation enhances rheumatoid arthritis fibroblast-like synoviocyte inflammatory responses

OBJECTIVE

Fibroblast-like synoviocytes (FLS) contribute to the pathogenesis of rheumatoid arthritis (RA), in part due to activation of the pro-inflammatory transcription factor NF-κB. Neddylation is modulated by the negative regulator of ubiquitin-like proteins-1 (NUB1). We determined whether NUB1 and neddylation are aberrant in RA FLS thereby contributing to their aggressive phenotype.

METHODS

RA or osteoarthritis (OA) FLS were obtained from arthroplasty synovia. RT-qPCR and Western blot analysis assessed gene and protein expression, respectively. NUB1 was overexpressed using an expression vector. NF-κB activation was assessed by stimulating FLS with IL-1β. Neddylation inhibitor (MLN4924) and proteasome inhibitor were used in migration and gene expression assays. MLN4924 was used in the K/BxN serum transfer arthritis model.

RESULTS

Enhanced H3K27ac and H3K27me3 peaks were observed in the NUB1 promoter in OA FLS compared with RA FLS. NUB1 was constitutively expressed by FLS but induction by IL-1β was significantly greater in OA FLS. The ratio of neddylated CUL1 to non-neddylated CUL1 was lower in OA FLS than RA FLS. NUB1 overexpression decreased NF-κB nuclear translocation and IL-6 mRNA in IL-1β-stimulated RA FLS. MLN4924 decreased CUL1 neddylation, NF-κB nuclear translocation and IL-6 mRNA in IL-1β-stimulated RA FLS. MLN4924 significantly decreased arthritis severity in K/BxN serum-transfer arthritis.

CONCLUSION

CUL1 neddylation and NUB1 induction is dysregulated in RA, which increases FLS activation. Inhibition of neddylation is an effective therapy in an animal model of arthritis. These data suggest that neddylation system contributes to the pathogenesis of RA and that regulation of neddylation could be a novel therapeutic approach.

Laser capture microscopy (LCM)-RNAseq for topological mapping of synovial pathology during rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is an autoimmune disease in which the joint lining, or synovium, becomes highly inflamed and majorly contributes to disease progression. Understanding pathogenic processes in RA synovium is critical for identifying therapeutic targets. We performed laser capture microscopy (LCM) followed by RNA sequencing (LCM-RNAseq) to study regional transcriptomes throughout RA synovium.

METHODS

Synovial lining, sublining, and vessels were captured by LCM from seven RA and seven osteoarthritis (OA) patients. RNAseq was performed on RNA extracted from captured tissue. Principal component analysis (PCA) was performed on the sample set by disease state. Differential expression analysis was performed between disease states based on log2 fold-change and q-value parameters. Pathway analysis was performed using Reactome Pathway Database on differentially expressed genes (DEGs) between disease states. Significantly enriched pathways in each synovial region were selected based on false discovery rate (FDR).

RESULTS

RA and OA transcriptomes were distinguishable by PCA. Pairwise comparisons of synovial lining, sublining, and vessels between RA and OA revealed substantial differences in transcriptional patterns throughout the synovium. Hierarchical clustering of pathways based on significance revealed a pattern of association between biological function and synovial topology. Analysis of pathways uniquely enriched in each region revealed distinct phenotypic abnormalities. As examples, RA lining was marked by anomalous immune cell signaling, RA sublining by aberrant cell cycle, and RA vessels by alterations in heme scavenging.

CONCLUSION

LCM-RNAseq confirms reported transcriptional differences between RA and OA synovium and provides evidence supporting a relationship between synovial topology and molecular anomalies in RA.

Myeloid-derived suppressor cell-derived osteoclasts with bone resorption capacity in the joints of arthritic SKG mice

Background

Myeloid-derived suppressor cells (MDSCs) are heterogeneous immature myeloid cells with immunosuppressive functions. It is known that MDSCs are expanded at inflammatory sites after migrating from bone marrow (BM) or spleen (Sp). In chronic inflammatory diseases such as rheumatoid arthritis (RA), previous reports indicate that MDSCs are increased in BM and Sp, but detailed analysis of MDSCs in inflamed joints is very limited.

Objective

The purpose of this study is to characterize the MDSCs in the joints of mice with autoimmune arthritis.

Methods

We sorted CD11b+Gr1+ cells from joints (Jo), bone marrow (BM) and spleen (Sp) of SKG mice with zymosan (Zym)-induced arthritis and investigated differentially expressed genes (DEGs) by microarray analysis. Based on the identified DEGs, we assessed the suppressive function of CD11b+Gr1+ cells from each organ and their ability to differentiate into osteoclasts.

Results

We identified MDSCs as CD11b+Gr1+ cells by flow cytometry and morphological analysis. Microarray analysis revealed that Jo-CD11b+Gr1+ cells had different characteristics compared with BM-CD11b+Gr1+ cells or Sp-CD11b+Gr1+ cells. Microarray and qPCR analysis showed that Jo-CD11b+Gr1+ cells strongly expressed immunosuppressive DEGs (Pdl1, Arg1, Egr2 and Egr3). Jo-CD11b+Gr1+ cells significantly suppressed CD4+ T cell proliferation and differentiation in vitro, which confirmed Jo-CD11b+Gr1+ cells as MDSCs. Microarray analysis also revealed that Jo-MDSCs strongly expressed DEGs of the NF-κB non-canonical pathway (Nfkb2 and Relb), which is relevant for osteoclast differentiation. In fact, Jo-MDSCs differentiated into osteoclasts in vitro and they had bone resorptive function. In addition, intra-articular injection of Jo-MDSCs promoted bone destruction.

Conclusions

Jo-MDSCs possess a potential to differentiate into osteoclasts which promote bone resorption in inflamed joints, while they are immunosuppressive in vitro.

Association of large joint involvement at the start of biological disease-modifying antirheumatic drugs and Janus kinase inhibitors with disease activity and drug retention in patients with rheumatoid arthritis: The ANSWER cohort study

AIM

To investigate the association of large joint involvement (LJI) with disease activity and drug retention in patients with rheumatoid arthritis (RA) who started receiving a biological disease-modifying antirheumatic drug or Janus kinase inhibitor.

METHODS

Patients with RA from a Japanese multicenter observational registry were enrolled. Our definition of large joints included the shoulder, elbow, hip, knee, and ankle joints. Linear mixed-effects models were used to examine changes in the clinical disease activity index (CDAI) score at Week 24 as the primary outcome, and drug retention rates were compared between patients with and without LJI using Cox proportional hazards models. We examined the potential effect modifications of changes in the CDAI by baseline characteristics.

RESULTS

Overall, 2507 treatment courses from 1721 patients were included (LJI, 1744; no LJI, 763). Although LJI was associated with significantly higher changes in CDAI from baseline at Week 24 (difference in change in CDAI: -5.84 [-6.65 to -5.03], p < .001), CDAI was significantly higher in patients with LJI over time. Retention rates were similar in both groups. The association of LJI with changes in disease activity was more prominent in patients with a short disease duration, negative anti-citrullinated peptide antibodies, and interleukin-6 receptor inhibitor (IL-6Ri) use.

CONCLUSION

Although LJI was associated with a greater reduction in disease activity from baseline, higher disease activity at baseline was not offset over time in patients with LJI, demonstrating that LJI is an unfavorable predictor. An early treat-to-target strategy using an IL-6Ri may be beneficial for patients with LJI.

Trends of disease activity in Japanese patients over 75 years with rheumatoid arthritis from 2014 to 2021- the ANSWER cohort study

OBJECTIVES

To investigate if disease activity among elderly RA patients over 75 years has changed over time in the real-world clinical setting.

METHODS

Data from an observational multicentre registry of RA patients in Japan were analyzed. The primary outcome was to evaluate the changes in the proportion of very elderly RA patients (over 75 years) who achieved remission and low disease activity, from 2014 to 2021. The secondary outcome was to identify factors associated with remission and low disease activity by comparing demographic and clinical characteristics among the patients who had a study visit within the study period, using multivariate logistic regression.

RESULTS

A total of 32 161 patient visits were identified from 2014 to 2021. The proportion of patients over 75 years increased from 16.5% to 26.9%, with biologics and targeted-synthetic disease modifying anti-rheumatic drugs (b/tsDMARDs) usage increasing and glucocorticoids usage decreasing, while conventional-synthetic DMARDs usage remained relatively stable. The proportion of RA patients over 75 years achieving remission and low disease activity significantly increased from 62.2% to 78.2% (p for trend < 0.001). A negative factor associated with achieving remission and low disease activity was glucocorticoid usage, seropositivity, and history of previous b/tsDMARDs use while MTX usage was associated positively, independent of other predictors.

CONCLUSIONS

In our cohort, disease activity among very elderly RA patients has improved over time. The study suggests the importance of using a treat-to-target approach in very elderly RA patients to improve clinical outcomes.

Impact of anti-squamous cell carcinoma antigen antibodies on serum squamous cell carcinoma antigen levels measured by chemiluminescent immunoassay and chemiluminescent enzyme immunoassay

OBJECTIVE

The serum squamous cell carcinoma antigen (SCCA) level is a well-known tumor marker for squamous cell carcinoma. In this study, we examined the impact of immunoglobulin (Ig)-bound macromolecular SCCA on serum SCCA levels measured by 2 different methods.

METHODS

Seventy-five serum samples with an SCCA level >5.0 ng/mL as determined by a chemiluminescent immunoassay (CLIA) were also analyzed using a chemiluminescent enzyme immunoassay (CLEIA). The levels of IgG- and IgA-type anti-SCCA antibodies, which form immunoglobulins and macromolecules, respectively, were determined using an enzyme-linked immunosorbent assay. An absorption test was performed to confirm the presence of anti-SCCA antibodies.

RESULTS

The correlation coefficient between the values measured by CLEIA and CLIA was 0.768. The ratio of SCCA levels measured by CLEIA to those measured by CLIA in 14 samples with IgG-type anti-SCCA antibodies was significantly lower than that in samples without these antibodies (P < .031). Absorption tests showed that SCCA levels measured by CLIA might be falsely high in samples with IgG-type anti-SCCA antibodies, probably due to reactions with SCCA1.

CONCLUSION

The level of SCCA as measured by CLIA and CLEIA methods correlate well, but the presence of SCCA antibodies can affect the results of the CLIA method.

Clustering of phosphatase RPTPα promotes Src signaling and the arthritogenic action of synovial fibroblasts

Receptor-type protein phosphatase α (RPTPα) promotes fibroblast-dependent arthritis and fibrosis, in part, by enhancing the activation of the kinase SRC. Synovial fibroblasts lining joint tissue mediate inflammation and tissue damage, and their infiltration into adjacent tissues promotes disease progression. RPTPα includes an ectodomain and two intracellular catalytic domains (D1 and D2) and, in cancer cells, undergoes inhibitory homodimerization, which is dependent on a D1 wedge motif. Through single-molecule localization and labeled molecule interaction microscopy of migrating synovial fibroblasts, we investigated the role of RPTPα dimerization in the activation of SRC, the migration of synovial fibroblasts, and joint damage in a mouse model of arthritis. RPTPα clustered with other RPTPα and with SRC molecules in the context of actin-rich structures. A known dimerization-impairing mutation in the wedge motif (P210L/P211L) and the deletion of the D2 domain reduced RPTPα-RPTPα clustering; however, it also unexpectedly reduced RPTPα-SRC association. The same mutations also reduced recruitment of RPTPα to actin-rich structures and inhibited SRC activation and cellular migration. An antibody against the RPTPα ectodomain that prevented the clustering of RPTPα also inhibited RPTPα-SRC association and SRC activation and attenuated fibroblast migration and joint damage in arthritic mice. A catalytically inactivating RPTPα-C469S mutation protected mice from arthritis and reduced SRC activation in synovial fibroblasts. We conclude that RPTPα clustering retains it to actin-rich structures to promote SRC-mediated fibroblast migration and can be modulated through the extracellular domain.

POS0432 MDSCs IN THE INFLAMMATORY JOINT OF SKG MICE HAVE BOTH T CELL SUPPRESSIVE ABILITY AND OSTEOCLAST DIFFERENTIATION POTENTIAL

Background

Myeloid-derived suppressor cells (MDSCs) are heterogeneous immature myeloid cells with suppressive functions (1). It is known that MDSCs are expanded in inflammatory sites after migrating from bone marrow (BM) or spleen. Rheumatoid arthritis (RA) is an autoimmune disease characterized as polyarthritis. Although previous reports indicate that MDSCs are increased in BM and spleen of arthritis model mice, detailed analysis of MDSCs in inflammatory joints is limited.

Objectives

The purpose of this study is to characterize the MDSCs in the joints of autoimmune arthritis.

Methods

We isolated CD11b+Gr1+ cells as MDSCs from joints (Jo-MDSCs), bone marrow (BM-MDSCs) and spleen (Sp-MDSCs) of arthritis-induced SKG mice, and investigated differential expressed genes (DEGs) among MDSCs from three tissues by microarray expression analysis. Furthermore, we analyzed the suppressive function of each MDSCs by investigating the effect of them on T cell -proliferation and the osteoclast differentiation of each MDSCs stimulated by M-CSF and RANKL.

Results

Microarray analysis revealed that Jo-MDSCs highly expressed immunosuppressive DEGs (Pdl1, Arg1, Egr2 and Egr3) compared to BM MDSCs or Sp MDSCs. In addition, Jo-MDCSs highly expressed NF-κB non-canonical pathway DEGs (Nfkb2 and Relb), which are related to osteoclast differentiation. BM-MDSCs differentiated into osteoclasts but didn’t suppress T cell-proliferation and Sp-MDSCs suppressed T cell-proliferation but didn’t differentiate into osteoclasts. On the other hand, Jo-MDSCs was found to have both functions: T cell suppression and osteoclast differentiation potential.

Conclusion

Jo-MDSCs have a strong inhibitory effect on T cell proliferation and have the ability osteoclast differentiation potential.

References

[1]Veglia F, Perego M, Gabrilovich D. Myeloid-derived suppressor cells coming of age. Nat Immunol. 2018;19(2):108–19.

Disclosure of Interests

None declared.

AB0036 BUTYRIC ACID SUPPRESSES MIGRATION OF MONOCYTE-DERIVED DENDRITIC CELLS BY INHIBITING MDIA1-MEDICATED ACTIN POLYMERIZATION

Background

Butyric acid is known to improve chronic inflammation such as inflammatory bowel disease and arthritis [1, 2]. Dendritic cells activate in inflammatory condition, migrate to regional lymph nodes, and activate naive T cells.

Objectives

In this study, we investigated the effect of butyric acid on the migration ability of monocyte-derived dendritic cells (moDC).

Methods

Human CD14+ Monocytes were purified by positive selection from PBMC using CD14 magnetic beads. Cells were cultured in the presence of GM-CSF (50 ng/ml) and IL-4 (20 ng/ml) for 5 days. After culturing for 5 days, cells were matured with LPS (1ug/ml) for 24 hours. Butyric acid was administered at different dose or period. Surface antigen on moDC was analyzed by flow cytometry (BD FACS VERSE). Migration assay was performed on Boyden chamber CytoSelect 24-Well Cell Migration Assay (5um). Actin was stained with Alexa Fluor 488 Phalloidin before and after migration assay. After administration with butyric acid assigned to each period and concentration, moDC were lysed for western blot analysis for evaluating signaling. Chemiluminescent signals were detected and calculated by Amersham Imager.

Results

We demonstrated that butyric acid decreased the CCR7 expression of moDC, which has a key role in DC homing to the lymph nodes and intestinal Peyer’s patches. We also showed that butyric acid decreased the migration ability of moDC. Furthermore, moDCs cultured with butyric acid showed a round shape and poor formation of dendrites and pseudopodia. Then we studied the effect of butyric acid on cytoskeleton, which plays an important role in migration and pseudopodia formation of DCs. Polymerized Actin (F-Actin) staining revealed that butyrate suppressed actin polymerization of moDC in a dose dependent manner. CDC42 works important role of lamellipodia and membrane protrusions. RhoA is upstream of mDia1, and mDia1 was reported to accelerate actin nucleation and elongation. We revealed that butyrate decreased the protein expression of mDia1, RhoA, and CDC42, while beta actin was not downregulated, by Western blot analysis. Our results suggested that butyric acid suppresses migration of moDCs by inhibiting mDia1-medicated actin polymerization.

Conclusion

Butyric acid suppresses migration of moDCs by inhibiting mDia1-medicated actin polymerization.

References

[1]Mafalda R Couto 1, Pedro Gonçalves 2, Fernando Magro 3, Fátima Martel, et al. Microbiota-derived butyrate regulates intestinal inflammation: Focus on inflammatory bowel disease Pharmacol Res. 2020 Sep;159:104947.

[2]Wenpeng Hui, Dapeng Yu, Zhong Cao, Xiwu Zhao, et al. Butyrate inhibit collagen-induced arthritis via Treg/IL-10/Th17 axis Int Immunopharmacol. 2019 Mar;68:226-233.

Disclosure of Interests

None declared

Effect of resolvin D5 on T cell differentiation and osteoclastogenesis analyzed by lipid mediator profiling in the experimental arthritis

Resolvins, are specialized pro-resolving mediators (SPMs) derived from n-3 polyunsaturated fatty acids. They contribute actively to the resolution of inflammation, but little is known concerning their role in chronic inflammation, such as in rheumatoid arthritis (RA). Here, we performed lipid mediator (LM) profiling in tissues from the paws of SKG arthritic mice using lipid chromatography (LC)/mass spectrometry (MS)/MS-based LM metabololipidomics. We found elevated levels of SPMs including resolvin D5 (RvD5) in these tissues. Moreover, RvD5 levels were significantly correlated with arthritis disease activity. From experiments to assess the role of RvD5 in the pathology of RA, we concluded that RvD5 suppressed Th17 cell differentiation and facilitated regulatory T cell differentiation, as well as inhibiting CD4⁺ T cell proliferation. Furthermore, RvD5 attenuated osteoclast differentiation and interfered with osteoclastogenesis. Targeting the resolution of inflammation could be promising as a novel treatment for RA.

Treatment with an Anti-CX3CL1 Antibody Suppresses M1 Macrophage Infiltration in Interstitial Lung Disease in SKG Mice

CX3C Motif Chemokine Ligand 1 (CX3CL1; fractalkine) has been implicated in the pathogenesis of rheumatoid arthritis (RA) and its inhibition was found to attenuate arthritis in mice as well as in a clinical trial. Therefore, we investigated the effects of an anti-CX3CL1 monoclonal antibody (mAb) on immune-mediated interstitial lung disease (ILD) in SKG mice, which exhibit similar pathological and clinical features to human RA-ILD. CX3CL1 and CX3C chemokine receptor 1 (CX3CR1), the receptor for CX3CL1, were both expressed in the fibroblastic foci of lung tissue and the number of bronchoalveolar fluid (BALF) cells was elevated in ILD in SKG mice. No significant changes were observed in lung fibrosis or the number of BALF cells by the treatment with anti-CX3CL1 mAb. However, significantly greater reductions were observed in the number of M1 macrophages than in M2 macrophages in the BALF of treated mice. Furthermore, CX3CR1 expression levels were significantly higher in M1 macrophages than in M2 macrophages. These results suggest the stronger inhibitory effects of the anti-CX3CL1 mAb treatment against the alveolar infiltration of M1 macrophages than M2 macrophages in ILD in SKG mice. Thus, the CX3CL1-CX3CR1 axis may be involved in the infiltration of inflammatory M1 macrophages in RA-ILD.

Soluble guanylate cyclase stimulator reduced the gastrointestinal fibrosis in bleomycin-induced mouse model of systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc) is a chronic autoimmune-mediated connective tissue disorder. Although the etiology of the disease remains undetermined, SSc is characterized by fibrosis and proliferative vascular lesions of the skin and internal organs. SSc involves the gastrointestinal tract in more than 90 % of patients. Soluble guanylate cyclase (sGC) stimulator is used to treat pulmonary artery hypertension (PAH) and has been shown to inhibit experimental skin fibrosis.

METHODS

Female C57BL/6J mice were treated with BLM or normal saline by subcutaneous implantation of osmotic minipump. These mice were sacrificed on day 28 or day 42. Gastrointestinal pathologies were examined by Masson Trichrome staining. The expression of fibrosis-related genes in gastrointestinal tract was analyzed by real-time PCR, and the levels of collagen in the tissue were measured by Sircol collagen assay. To evaluate peristaltic movement, the small intestinal transport (ITR%) was calculated as [dyeing distance × (duodenum - appendix)] - 1 × 100 (%). We treated BLM-treated mice with sGC stimulator or DMSO orally and analyzed them on day 42.

RESULTS

Histological examination revealed that fibrosis from lamina propria to muscularis mucosa in the esophagus was significantly increased in BLM-treated mice, suggesting that BLM induces esophageal hyperproliferative and prefibrotic response in C57BL/6J mice. In addition, the gene expression levels of Col3a1, CCN2, MMP-2, MMP-9, TIMP-1, and TIMP-2 in the esophagus were significantly increased in BLM-treated mice. More severe hyperproliferative and prefibrotic response was observed in the mice sacrificed on day 42 than the mice sacrificed on day 28. The ITR% was found to be significantly lower in BLM-treated mice, suggesting that gastrointestinal peristaltic movement was reduced in BLM-treated mice. Furthermore, we demonstrated that sGC stimulator treatment significantly reduced hyperproliferative and prefibrotic response of esophagus and intestine in BLM-treated mice, by histological examination and Sircol collagen assay.

CONCLUSIONS

These findings suggest that BLM induces gastrointestinal hyperproliferative and prefibrotic response in C57BL/6J mice, and treatment with sGC stimulator improves the BLM-induced gastrointestinal lesion.

SAT0011 COMBINED INHIBITION OF AUTOPHAGY AND GLUTAMINE METABOLISM SUPPRESSES CELL GROWTH OF RA SYNOVIOCYTES AND AMELIORATES ARTHRITIS IN SKG MICE

Background:

Immunometabolism is now recognaized to be crucial in the pathogenesis of rheumatoid arthritis (RA). We have recently shown that the expression of glutaminase 1 (GLS1), a key enzyme in glutaminolysis, is upregulated in fibroblast-like synoviocytes from RA patients (RA-FLS) and that GLS1 inhibition suppresses RA-FLS proliferation (1). However, glutaminolysis has been known to suppress autophagy by activating mTORC1 or counteracting ROS production (2). Given the possibility of autophagy upregulation following glutamiolysis inhibition, therapies targeting both autophagy and glutaminolysis may be more effective in suppressing cell growth of RA-FLS, yet the relation between glutaminolysis and autophagy in RA-FLS has not been investigated.

Objectives:

To examine the effects of inhibiting both glutaminolysis and autophagy on RA-FLS and autoimmune arthritis in SKG mice.

Methods:

GLS1 inhibitor, compound 968 (C968), was used to suppress glutaminolysis, and Chloroquine (CQ) was used to inhibit autophagy. To detect autophagy, the expression of ATG5 and LC3B was measured by real-time PCR and the production of LC3-II was analyzed by Western blotting. The formation of autophagic vacuoles was identified by immunfluorescense. Cell growth was evaluated by BrdU assay. Apoptosis was analyzed by flow cytometry staining with Annexin V-FITC and PI. C968 and CQ were administered subcutaneously to Zymosan A-injected SKG mice.

Results:

C968 upregulated the expression of ATG5 and LC3B, and increased the protein level of LC3-II in RA-FLS. C968 also facilitated autophagosome formation. These results suggested that inhibition of glutaminolysis promoted autophagy in RA-FLS. The combined treatment with C968 and CQ significantly suppressed cell proliferation of RA-FLS more strongly than did C968 or CQ alone. In addition, C968 combined with CQ increased the apoptosis rate, whereas either C968 or CQ alone did not. Furthermore, combination of C968 and CQ significantly attenuated the degree of arthritis in SKG mice, while C968 or CQ monotherapy did not (Figure).

Conclusion:

The GLS1 inhibitor C968 promotes autophagy in RA-FLS. C968 in combination with CQ reduces proliferation and enhances apoptosis in RA-FLS, and ameliorates the arthritis in SKG mice. Suppressing C968-induced autophagy may be a promising therapy for arthritis.

References:

[1] Takahashi S., et al. Arthritis Res Ther. 2017 Apr 11;19(1):76.

[2] Villar VH., et al. Autophagy. 2015;11(8):1198-208.

Acknowledgments :

None

Disclosure of Interests:

None declared

Subjective well-being among rheumatoid arthritis patients

AIM

Subjective well-being (SWB) is a psychological construct that is synonymous with happiness. Many variables including age, sex, income, employment, and marital status are related to SWB. Health is also an important determinant of SWB that can be adversely affected in patients with chronic conditions such as rheumatoid arthritis (RA). In this study, we evaluate the SWB of RA patients and compare it with that of healthy controls.

METHODS

We obtained the original dataset from the "Quality of Life Survey, 2013", which was conducted by the Economic and Social Research Institute, Cabinet Office, Government of Japan. In this survey, SWB was determined by asking participants to rate their happiness between 0 (very unhappy) and 10 (very happy). The survey also included a 56-point questionnaire regarding well-being-related variables. This questionnaire was administered to RA patients recruited from Kobe University Hospital, and clinical and treatment data were simultaneously collected.

RESULTS

Multivariate analysis revealed that RA patients with high or moderate disease activity had SWB scores that were similar to those of controls. However, the SWB scores of RA patients in remission or with low disease activity were higher than those of controls (P = .013). SWB was associated with household income, self-assessment of living costs, self-assessment of health, depression/ anxiety, and social connection.

CONCLUSIONS

For RA patients, achieving the therapeutic target can result in better SWB than that of healthy controls. Financial status, self-assessment of health, psychological stress, and social network are also important determinants for the SWB of RA patients.

Tofacitinib facilitates the expansion of myeloid-derived suppressor cells and ameliorates interstitial lung disease in SKG mice

BACKGROUND

Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is a sometimes life-threatening complication in RA patients. SKG mice develop not only arthritis but also an ILD resembling RA-ILD. We previously reported that tofacitinib, a JAK inhibitor, facilitates the expansion of myeloid-derived suppressor cells (MDSCs) and ameliorates arthritis in SKG mice. The aim of this study was to elucidate the effect of tofacitinib on the ILD in SKG mice.

METHODS

We assessed the effect of tofacitinib on the zymosan (Zym)-induced ILD in SKG mice histologically and examined the cells infiltrating the lung by flow cytometry. The effects of lung MDSCs on T cell proliferation and Th17 cell differentiation were assessed in vitro. We also evaluated the effects of tofacitinib on MDSCs and dendritic cells in vitro.

RESULTS

Tofacitinib significantly suppressed the progression of ILD compared to the control SKG mice. The MDSCs were increased, while Th17 cells, group 1 innate lymphoid cells (ILC1s), and GM-CSF+ILCs were decreased in the lungs of tofacitinib-treated mice. MDSCs isolated from the inflamed lungs suppressed T cell proliferation and Th17 cell differentiation in vitro. Tofacitinib promoted MDSC expansion and suppressed bone marrow-derived dendritic cell (BMDC) differentiation in vitro.

CONCLUSION

Tofacitinib facilitates the expansion of MDSCs in the lung and ameliorates ILD in SKG mice.

Additive effects of inhibiting both mTOR and glutamine metabolism on the arthritis in SKG mice

Glutamine metabolism and the mechanistic target of rapamycin (mTOR) pathway are activated cooperatively in the differentiation and activation of inflammatory immune cells. But the combined inhibition of both pathways was rarely investigated. This study investigated how inhibiting both glutamine metabolism with 6-diazo-5-oxo-L-norleucine (DON) and mTOR with rapamycin affects immune cells and the arthritis in a mouse model. We revealed that rapamycin and DON additively suppressed CD4⁺ T cell proliferation, and both of them inhibited Th17 cell differentiation. While DON inhibited the differentiation of dendritic cells and macrophages and facilitated that of Ly6G⁺ granulocytic (G)-MDSCs more strongly than did rapamycin, G-MDSCs treated with rapamycin but not DON suppressed CD4⁺ T cell proliferation in vitro. The combination of rapamycin and DON significantly suppressed the arthritis in SKG mice more strongly than did each monotherapy in vivo. The numbers of CD4⁺ T and Th17 cells in the spleen were lowest in mice treated with the combination therapy. Thus, combined treatment with rapamycin and DON additively ameliorated the arthritis in SKG mice, possibly by suppressing CD4⁺ T cell proliferation and Th17 differentiation. These results suggest the combination of rapamycin and DON may be a potential novel therapy for arthritis.

Acute Pulmonary Hypertension Crisis after Adalimumab Reduction in Rheumatoid Vasculitis

Rheumatoid vasculitis is a rare etiology for pulmonary hypertension (PH) in patients with connective tissue disease. We encountered a case of acute PH crisis in a case with rheumatoid vasculitis eight months after undergoing adalimumab reduction. Since no repetition of arthralgia occurred after the adalimumab reduction, we decided to not increase the dose of adalimumab. However, hemodynamic collapse thereafter developed and even though steroid pulse therapy was administered, the patient nevertheless died. The autopsy showed clusters of acute and chronic inflammation around the remodeled pulmonary arteries along with micro-thrombi in the vessel lumen. We should consider the possibility of critical worsening of PH as a phenotype of vasculitis related to immunosuppressive therapy reduction.

Myeloid-derived suppressor cells in non-neoplastic inflamed organs

BACKGROUND

Myeloid-derived suppressor cells (MDSCs) are a highly heterogeneous population of immature myeloid cells with immunosuppressive function. Although their function in tumor-bearing conditions is well studied, less is known about the role of MDSCs in various organs under non-neoplastic inflammatory conditions.

MAIN BODY

MDSCs are divided into two subpopulations, G-MDSCs and M-MDSCs, and their distribution varies between organs. MDSCs negatively control inflammation in inflamed organs such as the lungs, joints, liver, kidneys, intestines, central nervous system (CNS), and eyes by suppressing T cells and myeloid cells. MDSCs also regulate fibrosis in the lungs, liver, and kidneys and help repair CNS injuries. MDSCs in organs are plastic and can differentiate into osteoclasts and tolerogenic dendritic cells according to the microenvironment under non-neoplastic inflammatory conditions.

CONCLUSION

This article summarizes recent findings about MDSCs under inflammatory conditions, especially with respect to their function and differentiation in specific organs.

CD11b+Gr-1dim Tolerogenic Dendritic Cell-Like Cells Are Expanded in Interstitial Lung Disease in SKG Mice

OBJECTIVE

SKG mice develop interstitial lung disease (ILD) resembling rheumatoid arthritis-associated ILD in humans. The aim of this study was to clarify the mechanism underlying the lung pathology by analyzing lung-infiltrating cells in SKG mice with ILD.

METHODS

We assessed the severity of zymosan A (ZyA)-induced ILD in SKG mice histologically, and we examined lung-infiltrating cells by flow cytometry. Total lung cells and isolated monocytic myeloid-derived suppressor cells (MDSCs) were cultured in vitro with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4. The proliferation of 5,6-carboxyfluorescein diacetate N-succinimidyl ester-labeled naive T cells cocultured with isolated CD11b+Gr-1^dim cells and MDSCs was evaluated by flow cytometry. CD11b+Gr-1^dim cells were adoptively transferred to ZyA-treated SKG mice.

RESULTS

MDSCs, Th17 cells, and group 1 and 3 innate lymphoid cells (ILC1s and ILC3s) were increased in the lungs; the proportion of these cells varied with ILD severity. In this process, we found that a unique cell population, CD11b+Gr-1^dim cells, was expanded in the severely inflamed lungs. Approximately half of the CD11b+Gr-1^dim cells expressed CD11c. CD11b+Gr-1^dim cells were induced from monocytic MDSCs with GM-CSF in vitro and were considered tolerogenic because they suppressed T cell proliferation. These CD11b+Gr-1^dim cells have never been described previously, and we termed them CD11b+Gr-1^dim tolerogenic dendritic cell (DC)-like cells. Th17 cells, ILC1s, and ILC3s in the inflamed lung produced GM-CSF, which may have expanded CD11b+Gr-1^dim tolerogenic DC-like cells in vivo. Furthermore, adoptive transfer of CD11b+Gr-1^dim tolerogenic DC-like cells significantly suppressed progression of ILD in SKG mice.

CONCLUSION

We identified unique suppressive myeloid cells that were differentiated from monocytic MDSCs in SKG mice with ILD, and we termed them CD11b+Gr-1^dim tolerogenic DC-like cells.

Glutaminase 1 plays a key role in the cell growth of fibroblast-like synoviocytes in rheumatoid arthritis

Background

The recent findings of cancer-specific metabolic changes, including increased glucose and glutamine consumption, have provided new therapeutic targets for consideration. Fibroblast-like synoviocytes (FLS) from rheumatoid arthritis (RA) patients exhibit several tumor cell-like characteristics; however, the role of glucose and glutamine metabolism in the aberrant proliferation of these cells is unclear. Here, we evaluated the role of these metabolic pathways in RA-FLS proliferation and in autoimmune arthritis in SKG mice.

Methods

The expression of glycolysis- or glutaminolysis-related enzymes was evaluated by real-time polymerase chain reaction (PCR) and Western blotting, and the intracellular metabolites were evaluated by metabolomic analyses. The effects of glucose or glutamine on RA-FLS cell growth were investigated using glucose- or glutamine-free medium. Glutaminase (GLS)1 small interfering RNA (siRNA) and the GLS1 inhibitor compound 968 were used to inhibit GLS1 in RA-FLS, and compound 968 was used to study the effect of GLS1 inhibition in zymosan A-injected SKG mice.

Results

GLS1 expression was increased in RA-FLS, and metabolomic analyses revealed that glutamine metabolism was increased in RA-FLS. RA-FLS proliferation was reduced under glutamine-deprived, but not glucose-deprived, conditions. Cell growth of RA-FLS was inhibited by GLS1 siRNA transfection or GLS1 inhibitor treatment. Treating RA-FLS with either interleukin-17 or platelet-derived growth factor resulted in increased GLS1 levels. Compound 968 ameliorated the autoimmune arthritis and decreased the number of Ki-67-positive synovial cells in SKG mice.

Conclusions

Our results suggested that glutamine metabolism is involved in the pathogenesis of RA and that GLS1 plays an important role in regulating RA-FLS proliferation, and may be a novel therapeutic target for RA.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1283-3) contains supplementary material, which is available to authorized users.

Knockout of endothelin type B receptor signaling attenuates bleomycin-induced skin sclerosis in mice

Background

Endothelin-1 (ET-1) is important in the pathogenesis of systemic sclerosis (SSc). ET-1 binds two receptors, endothelin type A (ET_A) and endothelin type B (ET_B). Dual ET_A/ET_B receptor antagonists and a selective ET_A receptor antagonist are used clinically to treat SSc, and the effect of these antagonists on fibroblast activation has been described. However, the role of ET_B receptor signaling in fibrogenesis is less clear. This study was conducted to evaluate the profibrotic function of ET_B receptor signaling in a murine model of bleomycin (BLM)-induced scleroderma.

Methods

We used ET_B receptor–knockout (ET_BKO) mice, which are genetically rescued from lethal intestinal aganglionosis by an ET_B receptor transgene driven by the human dopamine β-hydroxylase (DβH)-gene promoter, and wild-type mice with DβH-ET_B (WT). BLM or phosphate-buffered saline (PBS) was administered subcutaneously by osmotic minipump, and skin fibrosis was assessed by dermal thickness, subcutaneous fat atrophy, and myofibroblast count in the dermis. Dermal fibroblasts isolated from ET_BKO and WT mice were cultured in vitro, stimulated with BLM or ET-1, and the expression of profibrotic genes was compared by quantitative PCR.

Results

Dermal thickness, subcutaneous fat atrophy, and myofibroblast counts in the dermis were significantly reduced in ET_BKO mice compared to WT mice, after BLM treatment. Compared with wild-type, dermal fibroblasts isolated from ET_BKO mice showed lower gene expressions of α-smooth muscle actin and collagen 1α1 in response to BLM or ET-1 stimulation in vitro.

Conclusions

ET-1–ET_B receptor signaling is involved in skin sclerosis and in collagen synthesis by dermal fibroblasts.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1011-4) contains supplementary material, which is available to authorized users.

[MMP-3 as a Biomarker of Disease Activity of Rheumatoid Arthritis]

The aim of this study was to confirm the clinical significance of serum MMP-3 measurement in the evalua- tion of disease activity and effectiveness of treatment in patients with rheumatoid arthritis (RA). MMP-3 was measured for 206 outpatients with RA during a period of 4 months, and also serially measured for RA patients treated with methotrexate(MTX) alone or together with infliximab (IFX). Serum MMP-3 was significantly correlated with CRP, SAA, and ESR. Significant correlation of serum MMP-3 was found not only with DAS28 (CRP) in female and male patients (p <0.0001 and p < 0.0051, respectively) but also with the EULAR classification criteria for the disease activity of RA. Among the items of DAS28(CRP), the strongest association of MMP-3 was found with swollen joint counts. Furthermore, MMP-3 levels increased with advances in Stage and Class of RA. MMP-3 levels gradually decreased 12 and 24 weeks after successful treatment with MTX (p=0.0188 and p=0.0179, respectively). Extent of the decrease was more prominent in patients with better response to MTX than in those with poor response. MMP-3 levels significantly decreased 6 weeks after IFX treatment and continued to decrease until 48 weeks. Significant decrease of MMP-3 level from before treatment was shown only in the good response group to IFX after 48 weeks of treatment. MMP-3 level was shown to be useful as a disease activity marker in RA patients. In addition, serial measurement of MMP-3 maybe helpful to evaluate the effect of treatments with MTX and IFX.

Metabolomics analysis of saliva from patients with primary Sjögren's syndrome

The recent development of salivary proteomics has led to the identification of potential biomarkers for diagnosing patients with primary Sjögren's syndrome (pSS). Here we sought to identify differentially produced salivary metabolites from pSS patients and healthy controls (HCs) that might be used to characterize this disease. We obtained salivary samples from 12 female pSS patients (mean age 44.2 ± 13.01) and 21 age-matched female HCs. The metabolite profiles of saliva were analysed by gas chromatography-mass spectrometry. The total metabolite levels in each of the samples were calculated and compared across the study participants. A total of 88 metabolites were detected across the study samples, 41 of which were observed at reduced levels in the samples from pSS patients. Principal component analysis (PCA) revealed a loss in salivary metabolite diversity in the pSS patient samples compared to the HC samples. The reduced presence of glycine, tyrosine, uric acid and fucose, which may reflect salivary gland destruction due to chronic sialoadenitis, contributed to the loss of diversity. Comparative PCA of the pSS patients revealed the presence of two subpopulations based on their metabolite profiles, and these two subpopulations showed a significant difference in the prevalence of major salivary glanditis (P = 0.014). In this study, we found that the salivary metabolite profile of pSS patients was less diverse than that of HCs and that the metabolite profiles in pSS patients were affected by the presence of major salivary glanditis.

IgG4-related disease manifesting as pericarditis with elevated adenosine deaminase and IL-10 levels in pericardial fluid

A 78-year-old female with massive pericardial effusion fulfilled diagnostic criteria for immunoglobulin G4 (IgG4)-related disease. Although her adenosine deaminase (ADA) level in the pericardial effusion was high, all the tests for tuberculosis infection were negative. Immunostaining of the pericardium biopsy specimen revealed remarkably increased IgG4-positive cells. This is the first report describing IgG4-related pericarditis with elevated ADA level. We also demonstrate the elevated interleukin-10 (IL-10) level in pericardial fluid and IL-10-producing T-cells in the pericardium.

Granulomatosis with polyangiitis (Wegener's granulomatosis) diagnosed by transbronchial biopsy from stenotic portion of mainstem bronchus

This report concerns a case of granulomatosis with polyangiitis (GPA) (Wegener's granulomatosis (WG)) with bronchus narrowing. Although nasal biopsy had been performed three times, no positive histology for GPA (WG) could be obtained. Flexible bronchoscopy revealed diffuse erythema, edema of the mucosa and stenosis of the right mainstem bronchus. Transbronchial biopsy identified granuloma with giant cells. These findings led to a diagnosis of GPA (WG). This case suggests that biopsy from the bronchus is useful for diagnosis of GPA (WG).

Role of imaging studies in the diagnosis and evaluation of giant cell arteritis in Japanese: report of eight cases

The objective of this study is to clarify the characteristics and imaging results of Japanese patients with giant cell arteritis (GCA). Eight patients with biopsy-proven GCA were enrolled. Their clinical data and imaging results were retrospectively examined from their medical records. All the patients met the criteria for the classification of GCA by the American College of Rheumatology. Although the clinical manifestations are similar to those previously reported, none of the eight patients presented ocular symptoms, and half of them presented jaw claudication. Ultrasonography (US) of temporal artery showed the halo sign in all the patients. Fluorodeoxyglucose positron emission tomography (FDG-PET) was performed in four patients and indicated the presence of aortitis of the patients. US is a quick and noninvasive test to detect inflammation of temporal artery, and FDG-PET is very helpful for early diagnosis of aortitis in GCA. Awareness of the disease and appropriate imaging tests will result in diagnosis of GCA.

Exogenous thrombospondin stimulates the proliferation of non-thrombospondin-producing cells

The effects of thrombospondin (TSP) on the proliferation of two different human carcinoma cell lines (KIM-1 and CW-2) were investigated. The characterization of these two carcinoma cells by immunohistochemistry using anti-TSP antibody and anti-TSP-receptor antibody showed that the KIM-1 had TSP-receptors and TSP, while the CW-2 had only TSP-receptors. The addition of exogenous TSP (10 or 20 microg/ml) to culture medium stimulated the cell proliferation of CW-2 but not that of KIM-1. The cell count for CW-2 was increased dosage-dependently from 10.3 0.6x104/ml at zero TSP concentration to 12.9 0.6x104/ml at 10 microg/ml TSP concentration and to 14.7 0. 4x104/ml at 20 microg/ml TSP (each p<0.0001). In conclusion, though TSP promoted the proliferation of non-TSP-producing cells, it did not promote proliferation of TSP-producing cells. Therefore, it is predicted that TSP was already at saturated activity concentration in the TSP-producing cell line (KIM-1).

[Analysis of nuclear DNA heterogeneity of the hepatocellular carcinoma (HCC)]

To evaluate the objective proliferative activity in HCC nuclear DNA contents were measured by means of microspectrophotometry and at the same time the immunohistochemical technique using anti-PCNA antibody was employed. Surgically resected 26 HCCs were analyzed in terms of cell proliferative activity and regional heterogeneity. The analysis was performed by immunohistochemical demonstration of PCNA and pathologic histochemical study in formalin-fixed, paraffin-embedded specimens and cytophotometric measurements of nuclear DNA contents in fresh specimens. The results were as follows. 1) Nine HCCs showed regional ploidy heterogeneity. 2) PCNA labeling index and histological grade of the marginal area was much higher than that of the central area. From these results, we concluded that in the process of the HCC progression proliferative activity was decreased in the central area and was not decreased in the marginal area.

C-CAM expression in the developing rat central nervous system

C-CAM, a transmembrane glycoprotein belonging to the immunoglobulin superfamily, can mediate intercellular adhesion by homophilic, Ca(2+)-independent binding. Immunohistochemical analysis of adult rat tissues has demonstrated that C-CAM is expressed in various epithelia, vessel endothelia, and hematopoietic cells. By molecular cloning and sequence analysis several isoforms differing both in the extracellular and the cytoplasmic domains have been found. Here we have analyzed the expression of C-CAM in the developing rat central nervous system. No neuronal expression was observed, but biochemical and immunohistochemical analyses demonstrated that C-CAM becomes expressed in the microvessels from embryonic day E-13; the intensity of the staining increased through day E-15 and then gradually decreased during the perinatal and early postnatal period. The expression of C-CAM in the walls of the microvessels was confirmed by in situ hybridization. Immunoelectron microscopy showed that C-CAM was localized both to the abluminal surface of the endothelial cells and to cellular processes of primordial pericytes where these two cell types are in contact with each other. No staining was found on the luminal endothelial cell surfaces or inter-endothelial cell contact areas. During the perinatal period C-CAM also became expressed on the opposite side of the pericytes and on other cells, possibly astrocytes, in contact with these areas of the pericytes. These observations suggest that C-CAM may be involved in heterotypic, homophilic adhesion between endothelial cells, pericytes and astrocytes, and in maturation of the vessel walls.

Detection of passage and absorption of chicken egg yolk immunoglobulins in the gastrointestinal tract of pigs by use of enzyme-linked immunosorbent assay and fluorescent antibody testing

Chicken egg yolk IgG can be absorbed and transferred as efficiently as colostral antibodies in the blood of neonatal pigs. Egg yolk IgG has a half-life of 1.85 days in newborn pig serum. This is shorter than the reported half-life (12 to 14 days) of homologous IgG in serum of pigs. Similar to colostral antibodies, egg yolk IgG absorption from intestine ceased at about 34 hours of age, after a logarithmic decrease in absorption rate from birth. Egg yolk IgG absorption inhibition time in the gastrointestinal tract took 1.73 hours to decrease by half. Egg yolk IgG was protective against experimentally induced diarrhea in pigs when it was administered at high dose, and multiple dosing was instituted. Adverse effects were not observed when chicken egg yolk IgG was administered orally to pigs.

Passive protective effect of chicken egg yolk immunoglobulins against experimental enterotoxigenic Escherichia coli infection in neonatal piglets

Passive protection of neonatal piglets against fatal enteric colibacillosis was achieved with powder preparations of specific antibodies against K88, K99, and 987P fimbrial adhesins of enterotoxigenic Escherichia coli. The antibody powders were obtained by spray drying the water-soluble protein fraction of egg yolks from immunized hens after the lipid components were precipitated with an aqueous dispersion of acrylic resins (Eudragit L30D-55; Rohm pharma). The anti-K88, -K99, and -987P antibody preparations reacted specifically against the corresponding fimbrial antigens in an enzyme-linked immunosorbent assay. The orally administered antibodies protected in a dose-dependent fashion against infection with each of the three homologous strains of E. coli in passive immunization trials with a colostrum-deprived piglet model of enterotoxigenic E. coli diarrhea. Scanning electron microscopy revealed adherence of enterotoxigenic E. coli in intestinal epithelial surfaces of control piglets, whereas in treated piglets treated with high-titer antibodies, a resistance to bacterial adhesion was observed. An enzyme immunoassay with avidin-biotin complex demonstrated specific local antibody activity in target areas of the small intestines. In vitro, E. coli K88+, K99+, and 987P+ strains adhered equally to porcine duodenal and ileal epithelial cells but failed to do so in the presence of homologous anti-fimbrial antibodies. Absorption of egg yolk antibodies with fimbrial immunosorbent removed the anti-fimbrial antibody fraction and reduced significantly the protective nature of the antibody preparation in a passive immunization experiment, suggesting that anti-fimbrial antibodies were the active components.

Immunocytochemical discovery of the 22- to 23-Kd subunit of cytochrome b558 at the surface of human peripheral phagocytes

A monoclonal antibody raised against cytochrome b558 reacted specifically with the 22- to 23-Kd protein, the small subunit of this cytochrome. Cytochemical studies showed that the epitope was located on the surfaces of human neutrophils and monocytes. The small subunit of cytochrome b558, therefore, was expressed at least in part on the outer surface of these cells.